Timepiece with flickering digital display

ABSTRACT

In an electronic timepiece using a digital display showing hours and minutes only, the fact that the timepiece is functioning can be evident by causing at least a portion of the digital display to flicker. The rate at which the flickering occurs is arranged to be close to one cycle per second, making it unnecessary to wait for periods as long as one minute in order to determine that the timepiece is functioning.

United States Patent 1191 Fujita Apr. 9, 1974 [54] TIMEPIECE WITH FLICKERING DIGITAL 2,542,021 2/1951 Fox 58/50 R DISPLAY 3,613,351 10/1971 Walton 58/23 BA 3,664,118 9/1970 Walton 58/50 R Inventor: m Fuma, g n Japan 3,630,015 12/1971 Lehovec 513/50 R l 3,672,155 6/1972 Bergey et al..... 521/50 R [73] Assgnee' Kabush'l Ka'sha Suwa se'kosha 3,576,099 3/1971 Walton 58/23 R Tokyo, Japan [22] Filed: Feb. 23, 1972 Primary Examiner-Richard B. Wilkinson Assistant ExaminerEdith Simmons Jackmon [21] Appl 232318 Attorney, Agent, or FirmBlum, Moscovitz, Friedman & Kaplan [30] Foreign Application Priority Data Feb. 25, 1971 Japan 46-8977 [57] ABSTRACT In an electronic timepiece using a digital display show- [52] US. Cl. 58/50 R, 58/23 BA, 340/249 ing hours and minutes only, the fact that the timepiece [51] Int. Cl. G04c 3/00, G04b 19/00 is functioning can be evident by causing at least a por- [58] Field of Search 58/23 R, 23 A, 23 BA, 50 R; tion of the digital display to flicker. The rate at which 340/3091, 336, 249; 350/160 LC the flickering occurs is arranged to be close to one cycle per second, making it unnecessary to wait for [56] References Cited periods as long as one minute in order to determine UNITED STATES PATENTS that the timepiece is functioning. 3,505,804 4/1970 Hofstein 58/50 R X 5 Claims, 6 Drawing Figures LD/ W05 R 0/ V/DER SHEET 2 0F 2 PAIENTEDAPR 9 m4 e per two seconds.

BACKGROUND OF THE INVENTION Digital display systems for timepieces can be arranged to show the hour, the minute and the second. Where the timepiece is a wristwatch, space limitations make it desirable that only the hour and the minute be shown. Since, in such a timepiece, the indicated time changes only once per minute, it-may be necessary to watch the timepiece for as long as one minute in order to make sure that the timepiece is functioning. It would be desirable that indication as to the functioning of the timepiece be given more frequently than once per minute. Moreover, it would also be desirable that the timepiece be useful for measuring intervals shorter than a minute.

SUMMARY OF THE INVENTION In an electronic timepiece, a high frequency oscillator supplies a time standard signal to a chain of frequency dividers. The frequency dividers then supply functioning.

FIG. 2 is a digital display in accordance with the present invention showing the hour and the minute with a colon therebetween;

FIG. 3 shows the display of FIG. 2 when one of the indicia comprising the colon is caused to flicker;

FIG. 4 is a block diagram indicating the electronic circuitry necessary for operating a timepiece in accordance with the present invention; and

FIG. 5 is a schematic representation of circuitry in accordance with the present invention employing liquid crystals as part of the display device.

DESCRIPTION OF THE PREFFERED EMBODIMENTS A digital display in accordance with the prior art is shown in FIG. 1(a) where the display device 6 indicates only the hour and the minute. In FIG. 1(b) is shown a In a preferred embodiment, the digital display is I based on the use of'liquid crystals. Furthermore, preferred rates of flickering are once per second and once Accordingly, an object of the present invention is to provide an improved timepiece wherein indication of the functioning of the timepiece is given by flickering of at least a portion of the display at a rate substantially greater than once per minute.

Another object of the present invention is to provide an improved timepiece wherein flickering of at least a portion of a digital display makes it possible to time periods with an accuracy of one second.

A further object of the present invention is to provide an improved timepiece wherein a digital ,display is based on the use of liquid crystals.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the article possessing the features, properties, and the relation of elements, which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference is bad to the following description taken in connection with the accompanying drawings, in which:

FIG. 1 (a) shows a digital display indicating the hour and the minute in accordance with the prior art;

FIG. 1(b) shows a digital display in accordance with the prior art indicating the hour, the minute and the second;

display device 7 in accordance with the prior art in which are shown the hour, the minute and the second. The space occupied by display device 7 is substantially larger than that occupied by display device 6 and requires inaddition, a substantially greater number of electrical connections (for a 7 segment display, 14 additional connections are required) which increases the cost of such a timepiece, and, moreover, where such a timepiece is a wristwatch requires additional space which may be awkward to provide.

FIG. 2 shows a display device 8 in accordance with the present invention wherein only the hour and the minute are directly displayed. However, the digits corresponding to the hour are separated from the digits corresponding to the minute by a colon 9. FIG. 3 shows the device of FIG. 2 in which the lower member 11 of the colon 9 is not illuminated. If the rate at which the lower member of colon is flickered on and off is substantially greater than once per minute then it becomes unnecessary to observe the timepiece for as long as 1 minute in order to determine whether the timepiece is functioning.

As is obvious, the same effect could be obtained by flickering any part of the display 8 such as the last digit or even all of the digits but it has been found preferable to maintain the visibility of the digits continuously and to use only the flickering of part of the colon as the indication that the timepiece is functioning.

The rate of flicker can range from a submultiple of once per second to several times per second. However, preferable rates are once per second and once per two seconds. Using a rate of once per second, it becomes convenient to'time operations, if so desired, to the nearest second.

The circuitry by which the digital display is controlled is shown in block diagram form in FIG. 4. An oscillator 12 driven by a battery (not shown) puts out a high frequency signal which is supplied to a divider 13. The chain of dividers 13, l4, l5 and 16 generates signals at a frequency of one cycle per second, one cycle per minute and one cycle per hour. The minute and hour signals are supplied to decoders l7 and 18 which respectively control the display of minutes and hours on the digital display device 8. At an intermediate stage 19, a signal is taken from the divider chain to circuit means 21 which causes the flickering of lower member 11 of colon 9.

In a preferred form, digital display 8 uses upper and lower panels to form chambers containing liquid crystals. The inner surfaces of the panels are coated with a conductor which is inert to the liquid crystals. At least the upper panel and the conductor on the interior surface of the upper panel must be transparent. Such an arrangement is shown in FIG. 5 where halfsecond pulses at a frequency of one per second are supplied to field effect transistor 21 which alternately activates and deactivates upper electrode 22 on upper panel 23. Lower electrode 24 on lower panel 26 is grounded in the arrangement shown. Upper electrode 22 and lower electrode 24 comprise the lower member 11 of colon 9.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above method and in the article set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

What is claimed is:

1. In an electronic timepiece employing a liquid crystal digital display cell showing digitally only the hour and the minute, the improvement comprising electronic circuitry for causing at least a part of said display to flicker at a selected, controlled frequency said circuitry including oscillator means for supplying a high frequencytime standard signal, a chain of frequency divider means for receiving said high frequency time standard signal and producing low frequency timing signals and an intermediate frequency signal, decoder means for receiving said timing signals from said divider means and actuating said digital display cell, circuit means for receiving said intermediate frequency signal and applying said signal to said part of said display cell to cause same to flicker at said intermediate frequency, said circuit means including at least one pair of complementary field effect transistors.

2. The timepiece as defined in claim 1, wherein said display flickers at a frequency between a small submultiple and a multiple of 1 Hz, at a frequency between a smalllsubmultiple and a small multiple of 1H2.

3. The timepiece as defined in claim 1, wherein said digital display includes a colon between said hour display and said minute display and-said part of said display which flickers is at least one of the two indicia comprising said colon.

4. The timepiece as defined in claim 1, wherein said flicker frequency is 1 Hz.

5. The timepiece as defined in claim 1, wherein said digital. display is based on the use of liquid crystals. 

1. In an electronic timepiece employing a liquid crystal digital display cell showing digitally only the hour and the minute, the improvement comprising electronic circuitry for causing at least a part of said display to flicker at a selected, controlled frequency said circuitry including oscillator means for supplying a high frequency time standard signal, a chain of frequency divider means for receiving said high frequency time standard signal and producing low frequency timing signals and an intermediate frequency signal, decoder means for receiving said timing signals from said divider means and actuating said digital display cell, circuit means for receiving said intermediate frequency signal and applying said signal to said part of said display cell to cause same to flicker at said intermediate frequency, said circuit means including at least one pair of complementary field effect transistors.
 2. The timepiece as defined in claim 1, wherein said display flickers at a frequency between a small submultiple and a multiple of 1 Hz, at a frequency between a small submultiple and a small multiple of 1H2.
 3. The timepiece as defined in claim 1, wherein said digital display includes a colon between said hour display and said minute display and said part of said display which flickers is at least one of the two indicia comprising said colon.
 4. The timepiece as defined in claim 1, wherein said flicker frequency is 1 Hz.
 5. The timepiece as defined in claim 1, wherein said digital display is based on the use of liquid crystals. 